Celery-Root Purée with Truffle Butter

Preparation Cover celery root and potatoes with cold salted water by 2 inches in a 4- to 6-quart heavy pot, then simmer, covered, until celery root is very tender, about 15 minutes. While vegetables are simmering, bring cream, truffle butter, salt, and pepper just to a simmer, stirring until butter is melted. Drain vegetables in a colander and transfer to a food processor. Add hot cream mixture in a steady stream, pulsing until smooth. (Alternatively, mash vegetables with hot cream mixture using a potato masher.) Cooks' note:Purée can be made 1 day ahead and cooled, uncovered, then chilled, covered. Reheat in an ovenproof dish, covered, in the oven or microwave until hot. *Available at specialty foods shops and D'Artagnan (800-327-8246).

Preparation Cover celery root and potatoes with cold salted water by 2 inches in a 4- to 6-quart heavy pot, then simmer, covered, until celery root is very tender, about 15 minutes. While vegetables are simmering, bring cream, truffle butter, salt, and pepper just to a simmer, stirring until butter is melted. Drain vegetables in a colander and transfer to a food processor. Add hot cream mixture in a steady stream, pulsing until smooth. (Alternatively, mash vegetables with hot cream mixture using a potato masher.) Cooks' note:Purée can be made 1 day ahead and cooled, uncovered, then chilled, covered. Reheat in an ovenproof dish, covered, in the oven or microwave until hot. *Available at specialty foods shops and D'Artagnan (800-327-8246).